Abstract:Based on the outcrop and drilling data, using the sequence stratigraphy, biostratigraphy and sedimentary theory, the Tarim Basin middle-upper Ordovician carbonate strata sequence framework and the relations between the sequence and the reef-shoal development are established. It is shown that the middle-upper Ordovician develops 5 third-grade sequences. The 3 third-order sequences of Lianglitage Formation in Tazhong area can be further divided into 7 fourth-order sequences, and the middle-upper Lianglitage Formation in Tazhong area and the Sangtamu Formation in Tabei area are contemporaneous heterotopic facies, so the Lianglitage Formation in Tazhong and Tabei is obviously a diachronism stratigraphic unit. The Liangligeta Formation in Tazhong area develops 5 periods of the reef beach body, the high-frequency sequences can well control the reef beach body development and is of great significance for the later reel-flat reservoirs prediction.